Identify the type of the given symbolic chemical reaction:
AB + CD \rightarrow CB + AD
a. Displacement reaction
b. Single displacement reaction
c. Double displacement reaction
d. Decomposition reaction
The Correct Answer and Explanation is:
The correct answer is c. Double displacement reaction.
Explanation:
A double displacement reaction (also known as a double replacement reaction) occurs when two compounds exchange components, typically ions, to form two new products. In this type of reaction, the cations and anions of the reactants switch places, forming new compounds. The general form of a double displacement reaction is:
AB + CD → CB + AD
Here, A and C are the cations (positive ions), while B and D are the anions (negative ions). In the reaction:
- A from AB pairs with D from CD, forming a new compound AD.
- C from CD pairs with B from AB, forming the new compound CB.
Key Characteristics of Double Displacement Reactions:
- Ion Exchange: The core of this reaction involves the exchange of ions between the two reactants. In this case, the cations (A and C) and the anions (B and D) swap places.
- Formation of Products: The new products CB and AD are formed from the original reactants AB and CD.
- Precipitation, Gas Formation, or Neutralization: Double displacement reactions often result in the formation of a precipitate, a gas, or a neutralized solution (as in acid-base reactions).
Example:
Consider the reaction between silver nitrate (AgNO₃) and sodium chloride (NaCl):
AgNO₃ + NaCl → AgCl + NaNO₃
- AB (AgNO₃) and CD (NaCl) exchange their ions.
- The result is the formation of CB (AgCl), a precipitate, and AD (NaNO₃), a soluble salt.
Why Other Options Are Incorrect:
- a. Displacement reaction: This is a general term for reactions where one element replaces another in a compound. It is not specific to the double displacement type, which involves the exchange of ions between two compounds.
- b. Single displacement reaction: In this reaction, one element displaces another from a compound, but this is not the case here, as both reactants AB and CD exchange parts.
- d. Decomposition reaction: A decomposition reaction involves a single compound breaking down into two or more simpler substances. This is not applicable to the provided reaction.